Long-distance relationship partners face a number of challenges such as reduced physical contact and intimacy as well as frequency and quality of in-person meetings. The success of a long-distance relationship can be affected, among other things, by the partner’s self-disclosure and attachment. Self-disclosure is considered a very important aspect of relationships with others. Research on self-disclosure in close relationships also emphasize the role of attachment where a secure attachment style is associated with a higher level of self-disclosure. According to that, higher result on avoidance dimension is associated with a lower level of self-disclosure, while the relationship of anxiety dimension and self-disclosure is less clear. Considering the lack of research on this topic, this study aimed to determine the relationship between the dimensions of attachment and self-disclosure in long-distance relationship partners, with respect to their gender. The study involved 258 participants (151 women and 107 men) aged 18 to 34, with an average age of 22. The Marital satisfaction scale (Ćubela Adorić and Jurević, 2006) adapted to extramarital relationships was used as a measure of relationship satisfaction, The Modified version of Brennan's Inventory of Close Relationships was used as a measure of attachment dimensions (Kamenov and Jelić, 2003), and The Revised Self-Disclosure Scale (Wheeless and Grotz, 1976; adapted Croatian version, Findrik, 2012) was used as a measure of self-disclosure. The results have shown there is no significant difference in the level of self-disclosure or the expression of the avoidance between men and women in long-distance relationship. Men and women in long-distance relationship are equally self-disclosing to their partners, and their results in the avoidance dimension do not differ. However, it has been found that women in long-distance relationship score higher on the anxiety dimension compared to men in long-distance relationship. Also, a statistically significant negative association of self-disclosure and dimensions of anxiety and avoidance was obtained. The more long-distance relationship partners self-disclose themselves, the lower score on anxiety and avoidance dimensions they achieve.